Means to immerse and tilt workholder



Oct. 14, 1969 c. B. COLEMAN MEANS TO IMMERSE AND TILT WORKHOLDER 3Sheets-Sheet 1 Filed Deo 19, 1966 mvsx TOR. qgorence 8. Coleman BY W 640440,,

Attorneys 1969 c. B. COLEMAN MEANS To IMMERSE AND TILT WORKHOLDER 3Sheets-Sheet 2 Filed Dec. 19, 1966 INVENTOR.

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Attorneys United States Patent ABSTRACT OF THEDISCLOSURE In immersingarticles'mounted on a vertically reciprocable platform in a liquidconfined in a tank, e.g., for dipping cartons in molten wax, theplatform is tilted back and forth on a horizontal axis, e.g., in onedirection during descent into the pool and in the opposite directionduring in the opposite direction during its ascent. The extentof rockingdepends upon the nature of the article, that is, upon the shapes of thepockets and the diversity inthe inclinations of the pockets; it may beas little as to 20 in the case of rectilinear cartons without flanges,but can be several'times as great if desired, e.g., the platform canascent, by-moving supporting cables (sprocket chains) vertically withdifferent speeds, thereby permitting the liquid to enter hollow pocketswithin the articles and thereafter to drain therefrom, e.g., to enteropen cartons and to drain out from the cartons.

"Iheinvention relates to a machine for immersing an article having a'hollow pocket in a pool of liquidwhich is confined in a tank to effectcontact of the liquid with all parts of the article, and isparticularly, but not exclusively, concerned with dipping assembled butopen cartons and their lids in molten wax to apply a thin coat of wax.

" In conventional practice paper boar-d cartons are given a coating ofparaffin or paraffin based wax (some waxes contain additives such asthermoplastics) by immersing the flat paper board, prior to assemblingof the fiat board into a finished carton, in a pool of molten wax. Thisprocedure often leads to cracks in the wax coating at the fold linesupon subsequently folding the cartons, eg at the exterior edges andcorners of the cartons. These cracks in the wax can cause-prematurefailure of the carton.

" When an assemble-d'open carton having a closed bottom is immersed in apool of molten wax, it is difficult to effect uniform contact of allparts of the carton and the When the open ends or mouths of the cartonsare directed downwards, there remain within the carton pockets of airwhich'are not reached by the wax;'and when the months are directedupwards throughoutthe dipping operation, wax cannot drain out from thecartons, causing a waste of wax and leaving excessive amounts of waxinside the cartons. It is not practicable to maintain the cartonsprecisely horizontal.

The instant invention is directedt'o providing apparatus for immersingobjects that. contain hollow pockets, particularly open-endedcartonsthat have closed. sides and bottoms, in a liquid in a manner thatall surfaces of the article are brought into contact with the liquid andre tention ofiexcess liquid within the pockets is obviated. :1In-another aspect, the invention is directed to providing ,a mechanismfor moving an article-supporting platform with a tilting motionduringwdescent into a pool of liquid and ascent from said pool, which issimple and economical.

7 Now according to one aspect of the invention, the platform whichsupports the articles to be immersed is rocked, eg on a substantiallyhorizontal axis during its descent into the liquid pool and subsequentascent from it, so that all air can escape from the 'pockets and bereplace-d by the liquid when the articles assume one inclination, andthe liquid can drain from the pockets and be replaced by air afterwithdrawal from the pool.

In a specific but preferred embodiment, the rocking motion includes onlytwo continuous motions, that is, the

platform is tilted in one direction during its descent and I be swungthrough or more.

According to another aspect of the invention, to which theabove-mentioned broad aspect is not restricted, the platform issupported by at least two vertically movable supports secured toopposite sides of the platform, and these supports are moved withdifferent vertical velocities, both up and down, so that the inclinationof the platform is continuously changed first in one and then in theother direction during a round trip of the platform. In a specificembodiment, each said support means comprises two flexible tensionmembers, herein for convenience called cables although suitably embodiedby sprocket chains, which are secured to the platform at spaced points,and the several cables are moved by drive pulleys the peripheries ofwhich move at different speeds. In one specific arrangement, all pulleysrotate at the same angular speed but those carrying cables secured toone side of the platform are larger in diameter than those secured tothe other side of the platform.

The inclination of the platform along a direction normal to its tiltingaxis is selected in accordance with the manner in which the articles aremounted therein. In any case, the positioning of the articles and thesaid inclination are such that all articles assume at least the twofollowing positions in succession: (l) the mouths of the pockets aredirected upwards while the article is immersed in the liquid; and (2)thereafter the mouths are directed downwards while the articles areabove the liquid. In the particular but simple arrangement in which theplatform has a planar (preferably not continuous) supporting surface andthe articles are rectilinear cartons placed thereon on their sides, withall open ends toward a common side of the platform (specifically, a sidewhich is parallel to the tilting axis), it is convenient to mount theplatform to tilt about said axis so that the said common side is higherthan the opposite side when the platform is fully lowered and lower whenthe platform is fully raised. The tilting axis is usually horizontal butthis is not essential.

The invention will be further described with reference to theaccompanying drawing forming a part of this specification and showing apreferred embodiment by way of illustration, wherein: l

FIGURE 1 is a perspective of a dipping machine constructed in accordancewith the present invention;

FIGURE 2 is a transverse section of the machine taken on a verticalplane;

FIGURE 3 is a perspective of a load of cartons when on the platform andabove the pool of liquid, parts of the elevating and tilting mechanismbeing shown and the platform appearing in phantom; and

FIGURE 4 is a perspective of the load of cartons when immersed in thepool of liquid, parts of the tank and platform appearing in phantom.

The machine includes a tank 5 which is open at the top and containsheating pipes 6 for maintaining a pool of liquid wax in moltencondition. Standards 7 are secured to the tank and extend upwardstherefrom, being interconnected by pairs of transverse and longitudinalstringers 8 and 9, respectively. The standards include vertical cornerplates 10 and transverse horizontal shafts 11 and 12 are mounted inthese plates, e.g., by suitable anti-friction bearings, not shown. Theshaft 11 carries, keyed or otherwise fixed thereto for rotationtherewith, drive pulleys 13, 13', 14 and 14'. The shaft 12 carries apair of idler pulleys 15 and 16. The shaft 11 is driven by a sprocketwheel 17 and chain or belt 18 from an electricmotor 19 which issupported from the standard by a platform 20. In this embodiment, allsix pulleys 1316 are sprocket wheels. The sprockets 13 and 13 are alike,

as are the sprockets 14 and 14, and the former have diameters greaterthan the latter, whereby their peripheries move faster than those of thelatter when all rotate at the angular speed of the shaft 11. Similarly,the sprocket 15 is, in this illustrative embodiment, larger than thesprocket 16, although this is not essential when these sprockets areindependently rotatable.

The platform 21 shown in FIGURES 1 and 2, is in this embodiment a wirecage having a flat bottom, four sides 22 and a hinged lid 23. Whileother forms of platform are suitable, a cage allows the flow of wax toand from the cartons, and lid 23 will resist buoyancy of the cartons.The platform is suspended by four sprocket chains 24, 25, 26 and 27. Thechains 24 and 25 jointly constitute one vertically movable support and,they are attached at spaced points to one side of the platform and runover the large drive sprockets 13 and 13', respectively, the chain 25passing additionally about the idler sprocket 15. The chains 26 and 27jointly constitute another vertically movable support, are attached tothe other side of the platform, and run over the small drive sprockets14 and 14', respectively, the chain 27 passing additionally about theidler sprocket 16. The ends of the chains 24 and 25 are both connectedto a weight 28, and the ends of the chains 26 and 27 are both connectedto another weight 29. The weights can move vertically to counterbalancethe weight of the platform, and may be guided by lugs 30 which areslidable along vertical rods 31 fixed to the standards 7. The lengths ofthe chains from the platform to the drive pulleys are such that when theplatform is in its uppermost position, as shown in FIGURES 1 and 2 theside of the platform at which the chains 24 and 25 are attached, ishigher than the platform side at which the other two chains areattached; and, the diameters of the sprockets on the shaft 11 are sorelated that, when this shaft is rotated and the platform moved to itslowermost position, the first-mentioned side of the platform is loweredmore rapidly than the other side. In the lowermost position, theinclination of the platform is reversed, as shown by the chain lines inFIGURE 2.

Limit switches 32 and 33 are mounted on one of the longitudinalstringers 9, as is shown in FIGURE 1. These switches have feeler armsthat are engaged by an abutment 34 carried by the chain 25. Theseswitches are connected to an electrical circuit for the motor 19 in amanner not shown in detail but obvious to those skilled in the art toperform the following functions: When the platform is in its uppermostposition, the motor 19 is started manually to turn the shaft 11 in adirection to pay out the chains. When the platform has reached itslowermost position, in which it is fully immersed in the pool of liquidwithin the tank 5, the abutment 34 strikes the limit switch 32. Thisreverses the motor to move the platform upwards. (Alternatively, it maymerely shut off the motor to afford a soak time, and the ascent can bebegun manually, or automatically by a time-delay device.) When theplatform has again been raised, the abutment 34 strikes the limit switch33 to stop .the motor.

Operation of the device will be described with reference to FIGURES 3and 4, as applied to coating cartons 35 and carton lids 36 with wax. Tothis purpose, the articles 35 and 36 are placed within the raised cageplatform 21 so that the open ends or months of all articles are directeddownwards, towards the lower side of the platform and the lid 23 is shutto prevent shifting of the articles.

Loading can be effected by a conveyor mechanism, if

desired employing an auxiliary cage, not shown because not a part ofthis invention. The motor 19 is then started,

and the sprockets 13, 13', 14, 14 pay out the chains to lower theplatform until the articles are fully immersed in .the liquid wax withinthe tank 5. Upon reaching the lowermost position, the platform is tiltedas appears in FIGURE 4, with the. mouths of the cartons 35 andlids 36directed slightly upwards. Air initially present within these articlesreadily escapesand all surfaces of the article are brought into contactwith the wax. When the platform is raised by reversing the motor 19, thecartons and lids are again tilted to their original position, shown inFIG- URE 3, permitting the liquid Wax to drain from the interiors intothe liquid pool.

It is evident that it is desirable to have the inclination of thearticles relative to the horizontal somewhat greater in the raisedposition than in the lower position, because drainage of the wax occursmore slowly than the escape of the gas. This is shown in FIGURE 2, inwhich the platform is inclined about 11 to the horizontal when in itsuppermost position but only about 6 to the horizontal when in itslowermost position.

I claim:

1. In apparatus for dipping articles in a liquid, which comprises a tankfor holding a pool of said liquid, 'a reciprocable platform for holdingsaid articles and adapted to be lowered into and raised from said pool,means for moving said platform up and down, the improvement of means forrocking said platform during the up and down movements thereof to varythe inclination of said articles during their movement, said means formoving the platform comprises at least first and second pairs ofpulleys, the pulleys of each pair having equal diameters but unequalwith respect to the other pair, first and second cables securedrespectively to opposite sides of the platform and extendingrespectively about a separate one of said pairs of pulleys, reversibledrive means for driving said pulleys at equal angular speeds whereby todrive said cables for effecting said rocking movement of the platform bymoving one of said sides more rapidly in the vertical direction than theother side.

2. Apparatus as defined in claim 1 wherein said pulleys are sprocketsand said cables are sprocket chains.

3. Apparatus as defined in claim 1 wherein said platform is formed ofwire mesh and has sides extending upwards from therefrom for retainingthe articles thereon.

4. Apparatus as defined in claim 1 wherein each cable comprises twoline-elements, said elements secured at spaced points on said platformand each element extending over a drive pulley.

5. Apparatus as defined in claim 4 wherein said means for the platformincludes at least two large-diameter and two small-diameter pulleysfixed on a common shaft for rotation at a common angular speed, andwherein the two line elements from one side of the platform extend overlarge-diameter pulleys and those from the other side extend oversmall-diameter pulleys.

References Cited UNITED STATES PATENTS 198,383 12/1877 OHanlon 254144 X561,712 6/1896 Lynch 134-'160X 657,354 9/1900 Muller 134 X 681,2758/1901 Stiefel et al 134-160 X 740,811 10/ 1903 Costello 11830 X 851,2364/1907 Hartog 118-30 2,643,662 6/1953 Bunce 134164 2,953,969 9/1960Pepple' 254144 X 3,047,436 7/1962 Zinty 134-160 X 3,320,963 5/1967Walker 134160 X 3,367,302 2/1968 Schloder et a1. 118-30 FOREIGN PATENTS9 1,161,741 1/1964 Germany.

500,270 11/1964 Italy.

MORRIS KAPLAN, Primary Examiner US. or. YX.R. 134M160; 254-144

